What is a 'barn raising'?
Wikipedia defines it in the following way:
A barn raising, also historically called a raising bee or rearing in the U.K., is a collective action of a community, in which a barn for one of the members is built or rebuilt collectively by members of the community. Barn raising was particularly common in 18th- and 19th-century rural North America. A barn was a necessary structure for any farmer, for example for storage of cereals and hay and keeping of animals. Yet a barn was also a large and costly structure, the assembly of which required more labor than a typical family could provide. Barn raising addressed the need by enlisting members of the community, unpaid, to assist in the building of their neighbors' barns. Because each member was entitled to recruit others for help, the favor would eventually return to each participant. 
Applied to wikis, barn raising involves the coming together of a community at a particular time and a particular place to start building something. Stewart Mader in Wiki Patterns defines a wiki barn raising in the following way:
A wiki BarnRaising is a planned event in which a community meets at a designated time to build content on the wiki together. One person alone can't build all the content in a wiki, and a community of people needs to understand how to use the wiki, and feel a sense of buy-in for it to become successful. A BarnRaising achieves this because people come expecting to learn how to use the wiki, and they are able to interact with each other as they work, thus strengthening community bonds and creating a support network that keeps people using the wiki.
Building Badge Wiki will involve several virtual barn raising sessions using the collective power, wisdom, and expertise of the community.
History of Badge Wiki Barn Raisings
- First barn raising session 26 July 2017 Blog post
- Second barn raising session 23 August 2017 Video Blog post
- In 2022, we started meeting monthly. Announcements are made in the Keep Badges Weird community!
Barn Raising Badges
There are different Badges that people can earn during the barn raisings or after working on their own on Badge Wiki. To claim one of the Badges, participants can go to a thread in the KBW Community and link to the things they have edited, written or changed. Afterwards they'll receive the Badge or multiple ones. Or they can claim them via the barn raising community calls.
Barn Raiser Badge
Description: This badge is issued to people who came to a barn raising for Badge Wiki. From small edits, restructuring the wiki or creating new pages, this badge is for community members who worked together to make Badge Wiki more useful.
Criteria: Earner came to a community barn raising session.
Barn Raiser x5
Description: The earner of this badge joined 5 different Badge Wiki barn raisings calls and contributed to overhauling Badge Wiki.
Criteria: The earner has to attend at least 5 barn raisings to receive the badge.
Badge Wiki Author
Description: A badge wiki author works collaboratively or alone to form pages that elucidate, define, present, or teach.
Criteria: The earner of this badge has to write content into the wiki and report back to the community by either talking about it in the Badge Wiki call or by posting it into the community.
Badge Wiki Fairy
Description: A Badge Wiki Fairy is active behind the scenes making things look good by adding pictures, colour, style and structure.
Criteria: The earner of this badge has to overhaul, style or restructure parts of the wiki and report back to the community by either talking about it in the badge wiki call or posting it into the community.
Badge Wiki Gardener
Description: A Badge Wiki Gardnener plants things, tends, prunes, tidies and generally nurtures the wiki.
Criteria: To earn this badge the earner has to garden parts of the wiki and report back to the community by either talking about it in the Badge Wiki call or posting it into the community.